Automatic letoff control



Y. H. KURKJIAN AUTOMATIC LET-OFF CONTROL March 12, 1946.

Filed March 2, 1943 2 sheets sheet 1 MaLrch 12, 1946. r Y. H. KURKJIAN 2,396,377

AUTOMATIC LET-OFF CONTROL Filed March 2, 1945 2 Sheets- Sheet 2 g] 1 wowbo'b )RvAA/rH. KuRrru/AA/ i WW? Patented Mar. 12, 1946 UNITED STATES PATENT OFFICE AUTOMATIC LETOFF CONTROL Yervant H. Kurkjian, Clifton, N. J.

Application March 2, 1943, Serial No. 477,743 4 Claims. (oi. 139-107) This invention relates to an automatic control for the let-off mechanism of looms, and the like, and has for one of its objects the production of a simple and efiicient automatic let-ofi control which will control the tension of the brake band of the warp beam in a proper manner to maintain a uniform tension of the warp threads carried by the warp beam.

A further object of this invention is the production of a simple and efiicient means for automatically shiftingthe position of the control weight relative to the brake band of a warp beam in a manner to retain a uniform tension upon the warp threads carried by the beam.

Other objects and advantages of the present invention will appear throughout the following specification and claims.

In the drawings:

Figure l is a side elevational view of one for of the automatic let-off control;

v Figure 2 is a fragmentary front elevational view of one end thereof;

Figure 3 is a side elevational view of a modified form of the invention;

Figure 4 is a fragmentary front elevational view of one end of the structure shown in Figure 3;

Figure 5 is a side elevational view of a further modified form;

Figure 6 is a side elevational view of a still further modified form;

Figure 7 is a fragmentary side elevational view of another modified form of the invention;

Figure 8 is a fragmentary sectional view taken on line 8-8 of Figure 7;

By referring to the drawings, it will be seen that H] designates the frame of the loom of a conventional type, which carries the warp beam l i also of the conventional type. Since the present invention relates to the automatic let-off control mechanism and not to the general loom construction, no effort is made to illustrate the detail construction of the loom itself, and only those parts vital to the invention are illustrated and described.

A tension control arm I2 is pivoted at its lower end It to the frame Ill, as shown in Figures 1 and 2. This arm it carries a warp contact roller it at its upper end for direct contact with the warp threads which are wound upon the warp beam E l, or the threadsupon a spool, as the case may be. A leverage control link i5 is plvotally connected, as at i6, to the arm l2, by means of a journal extending through the slot l1 formed in the frame ill. This link I5 carries a pair of transverse rollers 18 and Hi arranged one above the other at the outer end of the link l5, as shown in Figure 1. A tension spring I9 is connected at one end 26 to the frame l0, and at the other end 2! to the outer roller-carrying end of the link lE-see Figure 1.

A conventional flexible brake band 22 passes around the conventional brake drum 23 and is anchored at one end to the frame Ill, as at 24. The brake band 22 is connected at its opposite end to the outer end 25 of the brake lever 26. The brake lever 26 is pivoted to the frame in by means of a pivot 21. The inner end 23 of the brake lever 28 overlies and contacts the upper roller I8 of the link l5.

An intermediate lever 23 is pivoted, as at 38, to the frame It], and the outer end 3| contacts the under face of the lower roller l8 of the link IS. The downwardly oifset inner end 32 of the intermediate lever 29 fits under a transverse pin 33 carried by the weight lever 34. This weight lever 34 is pivoted to the frame ID, as at 35. The lever 34 underlies the lever 29 and carries'an adjustable weight 36 at its outer free end. The weight 35 may be adjusted as to Weight by adding additional weight plates and may be adjusted as to position by movement relative to. the adlusting notches 37 formed upon the weight lever 34.

By considering Figure 1, it will be seen that as the lever 12 swings toward the center of the beam H, and as the warp is unwound, the position of the rollers l8 and 18* will be shifted upon the levers 26 and 29, the roller [8 movingtoward the pivot 27 and the roller l8 moving away from the pivot 35. The intermediate lever 29 is provided with a rocking contact with the pin 33 of the weight lever 34!. As the leverage is shifted by the changing position of the rollers l8 and I8 relative to the levers 26 and 29, as a result of the movement of the arm I 2, the tension of the brake band 22 will be decreased in proportion to the weight of the weight 36 and the shifting leverage caused by the shifting of position of the rollers l8 and I8 relative to the levers 26 and 29. Consequently, as the warp is unwound from the beam H, the brake band 22 will be loosened due to the shifting leverage and in this manner the warp will at all times be kept substantially at a uniform tension. The tension of the brake band 22 will be regulated in ratio to the inwinding of the warp, the position of the tension control arm l3, and the leverage differential between the levers 26 and 29 occasioned by the shifting of the rollers I8 and w carried by the link l5. In this form of the invention, the weight 39 remains in a selected position and the pull of the weight 38 upon the brake band 22 is adjusted by the shifting leverage interposed between the weight 35 and the brake band 22. l he decreased leverage is provided as the size of the warp reduces and permits the arm l2 to swing toward the beam l l, thereby moving the roller-carrying end of the link l5 toward the pivot 21 and away from the pivot 39. In the form shown in Figure 1, it should be noted that the compound leverage arrangement is located directly below the warp and is confined within the area of the frame I 9. The weight lever 34 is pivoted near the front of the frame I8 and the free end of this weight lever 34 extends back under the intermediate lever 29 thereby avoiding any protruding parts beyond the front .of the frame l8.

By referring to Figures 3 and 4 it will be seen that a modified form of the invention is disclosed, wherein a frame 90 is illustrated of a conventional type, and a warp beam 4! is supported in a relative position to the frame 49 in any suitable or desired manner. The warp beam 9! carries a suitable brake drum 42 over which passes a brake band 43 of any suitable type, which band 93 is anchored at one end as at 44, to the frame 99, and the opposite end is secured to the outer end 45 of the brake lever 49. This brake lever 46 is pivoted as at 4'! to the frame 49. A control arm 48 is journaled, as at 49, upon the frame 48 and this control arm 49 carries a warp contact roller 59 at its upper end for contacting the warp threads wound upon the beam 9|. The journal 49 which is keyed to the arm 49 carries a gear wheel 5|, which gear wheel meshes with a rack 52 formed upon the under face of the weight lever 53.

The weight lever 53 supports a hanging weight 54 of a suitable type in a selected adjusted position, the weight 54 being suitably adjusted with respect to the notches 55 formed upon the upper face of the weight lever 53. This weight lever 53 is suitably guided through suitable guiding brackets 56 of any desired type. The weight lever 53 is provided with a pair of upstanding ears 5! between which ears is rotatably mounted a contact roller 58, the contact roller 58 engaging at all times the under face of the brake lever 46, the ears 5'! extending upwardly and spanning the lever 49 to hold the roller 58 in contacting posi tion with the lever 46.

A suitable compression spring 59 is adjustably carried by brackets 98 and contacts the arm 48 to normally hold the roller 58 of the arm 48 in contacting relation with respect to the warp wound upon the beam 4i. As the warp is unwound from the beam 4| in the direction of the arrow indicated in Figure 3, the roller 59 will move inwardly toward the center of the beam 4i thereby rotating the gear 55 in a counterclockwise direction and shifting the weight lever 53 in the direc-- tion of the arrow and thereby moving the roller 58 toward the pivot 41 and shortening the leverage upon the brake lever 46. Consequently, as the warp is unwound from the beam 4| the roller 58 will follow the warp as it reduces in diameter upon the beam 4| and consequently, the tension of the brake band 43 will be gradually and automatically decreased due to the shifting of the leverage which will naturally decrease the weight pressure upon the brake lever 49 and in this manner as the warp is withdrawn or unrolled from the beam 4| the tension of the brake band 43 above the frame 9 I.

will be automatically reduced in ratio to the amount of warp unrolled from the beam 4!, and thereby permit the warp to remain at all times at a substantially uniform tension, the control being regulated by the contact of the roller 59 with the warp which is wound upon the beam 9!.

By referring to Figure 5 it will be noted that I have shown a still further modified form wherein the frame BI is illustrated and a warp beam 62 is supported in any suitable or desired manner A brake band 93 is anchored at one end, as at 94, to the frame 9!, and the opposite end of the brake band 93 which passes over the brake drum 95 is connected, as at 89, to the outer end of the brake lever 51. The brake lever 61 is pivoted as at 98, and the opposite end of the brake lever El is provided on its under face with rack teeth 99 for meshing with a movable pinion Ill slidably mounted within a suitable guide TH carried by the inner end 72' of the weight lever 13.

A control arm 14 is pivoted at its lower end 15 to the frame 9! and this arm 14 is pivotally connected, as at 16, to the weight arm '53. The inner end 12 of the weight arm 13 is provided with rack teeth meshing with the movable pinion l9 and the arm 19 is provided with an extension which carries a warp contact roller H. The warp contact roller H is adapted to contact the warp which is wound upon the beam 92 and operates in a manner similar to that previously described, in the other forms. A suitable tension spring 78 engages the arm 14 to normally hold the arm 14 in an operative position to press the roller 17 against the warp which is wound upon the beam 62. As the arm 14 swings in toward the beam 62 in the direction of the arrow, the weight beam 13 will also be-moved in the direction of the arrow indicated on the beam and the movable pinion 18 will be moved toward the pivot 98 of the brake lever B! shortening the leverage and automatically reducing the tension of the brake band 63 in ratio to the swing of the arm l9 and in this way keeping the warp which is being unwound from the beam 52 at substantially uniform tension.

In Figure 6, there is shown another modified form of the invention wherein a frame 19 is illustrated and a beam 88 of a suitable type is supported above the frame 19, the rotation of the beam being controlled by a brake band 8i wh ch is anchored, as at 82, at one end, and is connected as at 83 at its opposite end to the brake lever 84. This brake lever 84 carries a control arm 85 which is pivoted as at 85, and this arm 85 carries a warp contacting roller 8'! at its upper end for contacting with the warp which is rolled on the beam 88. The lower end of the control arm 85 carries a roller 88 which contacts with the outer end 89 of the weight lever 99, and this weight lever 99 is pivotally connected, as at 9 l, to the frame 19. A drum 92 is also carried near the lower end of the control lever 85 and over the drum 92 passes a flexible cable 93 which cable is anchored as at 94 at one end and is connected to a slidable weight carriage 95 at its opposite end. As the warp is unwound from the beam 89, the roller 81 by contacting with the warp upon the beam 80 will permit the control lever 35 to swing inwardly toward the beam thereby moving the roller 88 outwardly in the direction of the arrow on the beam 99, and this movement will cause the cable 93 to pull the sliding weight carriage 95 inwardly and consequently reduce the tension of the brake band 8| upon the brake drum 88 in ratio to the amount of warp which has been unrolled or unwound from the beam 80.

As shown in Figures 7 and 8, a still further modified form of the invention is illustrated wherein a frame 96 is illustrated above which is mounted a conventional warp-supporting beam 91 upon which the warp 98 is wound. A brake drum 39 is carried by the beam 97 and a brake band we is anchored, as at "H, at one end to the frame 96 and is secured as at IE2 at its opposite end to the brake lever I03. This brake lever IE3 is pivoted as at I04 upon the frame 96 and carries a link I05 at its opposite end which link is pivotally connected to the inner end I06 of the weight lever I07, this lever I01 being pivoted as at I68 upon the frame 96.

A weight I09 is adjustably mounted in a selected position upon the weight lever I01 and a springpressed contact roller H0 is pivotally supported upon the lever I01 for contact with the warp 98 wound upon the beam 91. As the warp 98 is wound from the beam 97, the roller IIE) will be moved to the dotted position shown in Figure 7, reducing the pressure upon the weight beam I01 and also reducing the tension of the brake band III upon the brake drum 99 in a manner similar to that described in the foregoing forms.

It should be understood that certain detail changes in the structure illustrated may be em ployed without departing from the spirit of the invention and it should be borne in mind that the important feature of the present invention is the means for automatically controlling the tension of the brake band in ratio to the amount of warp which is unwound from the supporting beam thereby keeping the warp at a constant or substantially uniform tension.

Attention is directed to my co-pending application Serial No. 504,180, filed September 28, 1943 relating to Control for let-01f mechanism of looms, which is a continuation in part of this application; and to application Serial Number 504,181, filed September 28, 1943, now Patent No. 2,355,656, relating to Automatic control for let-off mechanism of looms; and to application Serial Number 504,182, filed September 28, 1943, now Patent No. 2,357,336, relating to Automatic control for the let-01f mechanism of looms, the latter two applications being divisions of the instant application.

Having described the invention, claimed is:

1. An automatic let-off control mechanism of the class described comprising, a beam forming part of said mechanism, a warp wound upon the beam, a brake drum carried by the beam, a brake band passing over the drum, a brake lever mounted adjacent the drum, the brake band engaging one end of the brake lever, a pivot supporting the brake lever, a swinging warpwhat is engaging arm, a pressure lever engaging said brake lever to one side of said pivot, and a, rack and pinion connection between said pressure lever and said warp-engaging arm for shifting the pressure lever relative to the brake lever as said warp-engaging arm swings.

2. An automatic let-oif control mechanism of the class described comprising, a beam forming part of said mechanism, a warp wound upon the beam, a brake drum carried by the beam, a brake band passing over the drum, a brake lever mounted adjacent the drum, the brake band engaging one end of the brake lever, a pivot supporting the brake lever, a rack carried by the brake lever, a pivoted warp-engaging arm, a weight arm pivoted to the warp-engaging arm, a rack carried by the weight arm, and a pinion contacting the racks and movable therebetween.

3. An automatic let-off control mechanism of the class described comprising a beam forming part of said mechanism, a warp wound upon the beam, a brake drum carried by the beam, a brake band passing over the drum, a brake lever mounted adjacent the drum, the brake band engaging one end of the brake lever, a pivot supporting the brake lever, a swinging warp-engaging arm, a pressure lever mounted adjacent the brake lever, means connecting the pressure lever with said warp-engaging arm for shifting said pressure lever relative to'said brake lever as said warp-engaging arm is swung, and contact means interposed between the brake lever and pressure lever located to one side of the pivot of said brake lever and shiftable as said pressure lever is shifted by the swinging of said arm to vary the leverage of said pressure lever upon said brake lever in proportion to the amount of warp which is carried by said beam.

4. An automatic let-off control mechanism of the class described comprising a beam forming part of said mechanism, a warp wound upon the beam, a, brake drum carried by the beam, a brake band passing over the drum, a brake lever mounted adjacent the drum, the brake band engaging one end of thebrake lever, a pivot supporting the brake lever, a shiftable pressure-creating means contacting the brake lever at a point spaced from said pivot, ,a swinging warp-engaging arm, and automatic means interposed between the brake lever and warp-engaging arm for shifting the position of the pressure-creating means relative to said pivot in ratio to the movement of said warp-engaging arm and the amount of warp unwound from said beam in a manner whereby the tension upon the brake drum will be proportionately reduced as the warp is let ofi to thereby maintain a constant uniform tension upon the warp while the war is being let off.

. YERVANT H. KURKJIAN. 

